IT IS A UNIQUE, sometimes surreal sensation to dive in the blue with sharks. Far from shore, in open water several hundred metres deep, shades of sunlight descend beneath you, and disappear into a dark unfathomable chasm.
Add to the feelings of overt exposure that this generates the notion that somewhere below and beyond the periphery of your vision sharks are approaching, and you could be forgiven for feeling some disquiet. The levels of excitement ebb and flow as your natural curiosity and fear vie for attention.
This kind of bluewater diving is not for the faint of heart or unpractised diver still ill at ease in the water. With no points of reference from the sea floor or an adjacent reef, it’s easy to become disorientated. Self-awareness and good buoyancy control are essential.
Throw a few inquisitive sharks into the equation and the situation can get really interesting. Suspended in an unfamiliar three-dimensional world, your mind races in a heightened state
of awareness, just when your vision and vestibular canals suffer in sensory deprivation.
It was in this scenario and state of mind that I saw my first blue shark.
I am a diver from Pico Island in the Azores, and I work as the resident biologist for CW Azores, a whale-watching and diving business. The Azores are a beautiful archipelago of nine islands lying in the middle of the Atlantic Ocean. More than 600 miles west of Portugal (a 2.5 hour flight from Lisbon), they are at Europe’s western fringe.
Pico is the most eye-catching island; a huge strato-volcano rising 2350m above the sea. Around its coast, layers of basaltic lava flows have been etched by countless waves to create an impressive seascape. Close to shore you can dive a labyrinth of arcades, gullies, caverns and drop-offs.
Here you can find an exciting mix of coastal and pelagic marine life. The more adventurous can also venture offshore to dive distant sea-mounts with mobula rays, or in blue water
with the elusive blue and mako sharks.
Shark-diving in the Azores is a recent phenomenon. It also provides a unique opportunity for divers in Europe to see blue and mako sharks in relatively warm water with excellent visibility.
For us it arose from a successful project carried out in collaboration with professional underwater photographer Jan Reyniers. After two years of exploration, looking for ways
to photograph these elusive animals, we have now established how and where to find the sharks with repeated success.
Small groups of divers can be taken from Pico to points offshore where these sharks can be lured in close.
Blue sharks can be seen on every trip, but the lucky also get extraordinary chances to see the open ocean’s top predator and fastest fish, the mako.
MY FIRST BLUE SHARK rose tentatively from the depths. Its approach was sanguine, almost hypnotic. As I watched, mesmerised, my fear was immediately overcome by its sublime beauty and economy of movement. Cautious and aloof, it turned away from me before descending back into the deep.
In late summer, the sea surface temperature around the Azores is around 23°C, well above the 7-18°C range the sharks prefer. In these warmer waters, blue sharks regularly rise and fall through the water column in search of prey near the surface, but also to regulate their temperature.
My shark sought sanctuary in the cool dark depths beneath me. For a while it repeated this activity, yo-yoing between the light and dark, sniffing out the bag of chum, tasting the water, artfully assessing the risk the other divers and I posed with the bait. Its initial forays were very cautious, non-threatening, even timid. Any sudden movement from a diver to either point a camera or even just a finger could send it scuttling back to the depths.
Gradually, however, it gained confidence, and with every ascent it grew bolder. Indeed, once it had sampled the bait and had received a few titbits thrown from the boat, it became downright curious.
Any diver present was closely inspected, a heart-stopping eyeball-to-eyeball encounter. Some of us were even brushed against, receiving a tactile test from its sensitive lateral line, as well as detailed views of the Ampullae of Lorenzini under its nose.
These two sense organs are well-developed in blue sharks. The lateral line comprises a strip of sensory cells that run head-to-tail along the body. They detect subtle changes in water pressure.
The Ampullae of Lorenzini pores detect weak bio-electrical signals and maybe even geo-magnetic fields.
The long snout is clearly peppered by many of them. It must be especially sensitive, and very useful in their nomadic lifestyle.
Up close, blue sharks are a blaze of indigo, nose tipped in bronze, incredibly beautiful. Slim and lithe, with long pectoral fins, their supple form exudes a physical perfection that only an eternity of evolution could yield.
Close encounters enthral and leave you awe-struck. To experience them, however, needs more than just luck – it requires chum and patience.
Fortunately, in the waters off Pico Island at the right time of year it is normally only a question of when rather than if they will be seen.
Blue sharks are synonymous with the open ocean, the deep blue. In this pelagic zone, feeding opportunities are few and far between. Few sharks expend energy more frugally than blue sharks. Every aspect of their biology is designed to maximise their chances of finding potential prey with the least effort.
To search most efficiently, the sharks often disperse widely. Only when one picks up our scent trail and crosses the slick of chum do we get to see them. Until then, we must wait.
ETHEREAL CREATURES, blue sharks are drifters. Capable of extensive ocean-wide migrations, they effortlessly cruise the world’s temperate and tropical seas.
Curiously, all the blues I have encountered in the Azores so far have been female, but there may be a good reason for this. Recoveries of tagged sharks have shown that female blues are highly migratory in the North Atlantic. They regularly traverse the ocean.
Crossing from North America to Europe and west Africa, they pass by the Azores before circling back, often via the Caribbean.
Most males, in contrast, are comparatively sedentary, and seem to stay around the eastern seaboard of North America. Perhaps this is also where they intercept the travelling females and breed.
Sharks are long-lived animals; they grow slowly, mature late and produce relatively few offspring, especially compared to bony fish like herring.
Their life strategy is more similar to that of marine mammals than other species of fish.
Unfortunately, this similarity means that their exploitation by fisheries has greater impact on their populations. Sharks produce too few young to cope. When fisheries remove adult sharks from the population, their numbers decline more rapidly and recover less well than other fish stocks.
Best estimates suggest that North Atlantic populations of blue shark may have declined by 30% since the 1950s, but accurate estimates of the decline are hard to obtain.
Most of the world’s catches of sharks are taken incidentally, as bycatch. Records are not prioritised and, though potentially substantial, little data is available. In the Azores, for every swordfish caught in long-line fisheries 10 sharks (usually blues) are also taken.
BLUE SHARKS ARE ALSO DELIBERATELY TARGETED, and dominate the Hong Kong shark-fin market. New technologies such as blast-freezing have enabled new markets to emerge in distant oceans. Just beyond the Azorean fisheries Exclusive Economic Zone (EEZ), and sometimes within it, Korean, Japanese as well as Spanish boats all vie for space.
Valiant attempts by the Portuguese authorities to police the Azorean EEZ are encouraging, but overall the global shark fishery shows little sign of sustainability. Worldwide every year
100 million sharks are lost, an estimated 750,000 blues from the North Atlantic.
Blue sharks can reach nearly 4m in length, but most sightings of large individuals are now found in dusty record books rather than the sea.
There is hope, however, and it lies in education and changing public perception. Diving with sharks is one way to do this, as well as experience these wonderful animals.
In addition, where demand for shark diving increases, local industries can benefit far more from sharks alive. If sharks can be admired rather than maligned, if their continued annihilation can provoke public outcry rather than public indifference, then perhaps policy change can be invoked so that these extraordinary predators can reign free in our oceans.
The Azores are probably the best place in the world to dive with and photograph blue sharks. Visibility is unparalleled elsewhere, and the light often exceptional.
In late summer the seas are warmest, and encounters reliable. There can be few better opportunities to take breathtaking images.
Archive | 
